of 4
Supporting Information:
Electrical Characteristics of the Junction Between PEDOT:PSS and
Thiophene
-
Functionalized Silicon Microwires
Jared P. Bruce
a†
, Derek R. Oliver
b
, Nathan S. Lewis
c
, Michael S. Freund
a
*
a)
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
b)
Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
c)
Division of Chemistry and Chemical Engineering, Califo
rnia Institute of Technology, Pasadena, California, USA
Corresponding Author: Dr. Michael Freund: msfreund@fit.edu
S
-
1
Figure
S
1
:
a) Large bias (
-
1 to 1V) of native oxide
without the presence of thiophene
n
-
Si/PEDOT:PSS junction. Under low bias
conditions (
-
100 to 100 mV) the response
was
ohmic but extremely resistive. b)
Semi
log plot of the oxide junction indicating
the i
R
loss at the intersection of the expected light
limited current
. The i
R
loss in
n
-
Si/PEDOT:PSS junction with native oxide at
the interface
was
well over 500 mV and is expected to limit the current flow in the system.
Table
S1
:
Ratios of silicon oxide peak to silicon bulk peak in Si 2p spectrum
. Standard deviation for all samples was 1%.
Reaction
time of 0 is
a methyl terminated sample
for comparison.
Reaction
Time (min)
No Backfill
-
Fresh
No Backfill
1
month ambient
Backfill
-
Fresh
Backfill
1
month Ambient
0
-
-
7.45
8.57
30
4.03
7.42
4.29
10.72
60
7.93
12.47
4.53
7.07
120
7.15
5.39
5.13
6.65
a
)
b
S
-
2
Figure
S2
:
n
Si microwire sample that ha
d
been functionalized 60
min
in thienyllithium solution. After 1 month of exposure to
ambient conditions, the
S 2s peak indicative of thiophene present on the surface
was
still present and no shifting or broadening of
the signal that may indicate a chemical change to the group from oxidation
was observed
.
The ratio of
the
S 2s to Si 2p bulk
was
9% while the expos
ed samples after 1 month
had
a ratio of 7%.
S
-
3
Figure S3: Thiophene functionalized (30 min) p
-
type wire/ PEDOT:PSS junction characteristics. Non
ohmic behaviour is
observed over large bias regions, however over the low bias r
egion (inset), ohmic behaviour is observed.
Figure S4:
Light microscope image of typical electrical characterization setup at 400x.